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The Summitville Mine in Colorado has become a case study of environmental damage as a result of mining. Gold was mined there from 1870 until 1992. In 1994 the U.S. Environmental Protection Agency (EPA) declared the area a Superfund site. Some of the following events affected the environment at the mine: Geologic characteristics at the mine site contributed to the generation of both natural and mining-related acid drainage; the height of the containing ecosystem the interacting system of a biological community and its nonliving environmental surroundings remediation cleanup or other methods used to remove or contain a toxic spill or hazardous materials from a Superfund site or for the Asbestos Hazard Emergency Response program topography the physical features of a surface area including relative elevations and the position of natural and man-made (anthropogenic) features leach solution in mining: chemical solution sprayed on ore to extract metal

French drain buried plastic tubing with numerous holes, to collect or disperse water leach pad in mining: a specially prepared area where mineral ore (especially gold) is heaped for metal extraction watershed the land area that drains into a stream; the watershed for a major river may encompass a number of smaller watersheds hydrology the science dealing with the properties, distribution, and circulation of water dike for cyanide leach solutions (used to chemically extract gold) was below the level required for snowstorms and spring runoff; broken pump lines and a French drain beneath the leach pad caused cyanide-contaminated solutions to be released into the local watershed; several waste rock piles at the mine reacted with rain and snowmelt to form acidic waters that flowed into area streams; an underground tunnel released large volumes of contaminated waters; and mining deforested much of the land. Remediation of the site has included such projects as backfilling mine waste into existing open pits, which reduces polluted water percolating into the ground; plugging underground tunnels; and replanting. Remediation is ongoing with the goal of restoring the nearby Alamosa River to support aquatic life; the U.S. Public Health Service classified this site as "no apparent public health hazard."

Another case study is the Iron Mountain Mine in California, which the EPA declared a Superfund site in 1983. Mining for copper, gold, silver, and zinc began in 1879 and continued until 1963 using underground and open-pit methods. The site contains inactive mines and numerous waste piles from which harmful quantities of untreated acidic, metal-rich waters were discharged. Mining operations fractured the mountain, changing the hydrology and exposing the mineral deposit to oxygen and water, which resulted in intense acid mine drainage into nearby creeks and waterways. These caused numerous fish kills and posed a health risk to the area drinking water. Some current remediation projects include: capping areas of the mine and the diversion of nearby creeks, both of which serve to reduce surface water contamination; construction of a retention reservoir to control the area source acid mine drainage discharges; enlargement of a landfill to provide an additional thirty years of storage capacity for heavy metals sludges; and construction of a significant upgrade to facilities in mine tunnels to assure safe travel for workers and equipment to perform maintenance and routinely remove mine wastes from the tunnels and other projects. see also Acid Rain; Heavy Metals; Mining; Superfund; Water Pollution.

Internet Resources

"Hazardous Materials and Waste Management Division Summitville Mine." Colorado Department of Public Health and Environment, 2002. Available from http://cdphe.state.co.us.

"Iron Mountain Mine." U.S. Environmental Protection Agency Document EPA CAD980498612. U.S. Environmental Protection Agency, 2001. Available from http://epa.gov/superfund/sites.

Jorgenson, Pat. "World's Most Acidic Waters Are Found Near Redding, California." U.S. Geological Survey, 2000. Available from http://ca.water.usgs.gov.

"Public Health Assessment Summitville Mine Del Norte, Rio Grande County, Colorado." U.S. Department of Health and Human Services, 1997. Available from http://atsdr.cdc.gov.

Michael J. McKinley

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